Methodologies to measure the sustainability of materials – focus on recycling aspects

Abstract

What environmental constraints will materials have to face in the future? Can current measurement tools like LCA (Life Cycle Analysis) support the choices of material and adapt to these constraints to pave the way to a sustainable world? Are there some alternative or complementary approaches to enhance the quality of information for decision makers? The aim of this article is to provide answers to these three questions. The society of tomorrow, in the second half of the 21st century, will be a society where the circular economy will play a more important role and thus will help reduce materials waste. This is a critical aspect of sustainability. To get there, the decisions have to be enlightened and fair, because the decisions (or non-decisions) made today shape the world that future generations will have to manage. Furthermore, Lord Kelvin used to say: “what you can’t measure, you can’t improve”. Therefore, these decisions have to be supported by measurement tools that will properly capture the stakes of reuse and recycling at the end of life of products. Today, LCA is the common tool used to address this matter. However, the present article has shown that LCA cannot incorporate the whole complexity of sustainability. LCA is good at considering micro-scale issues, comparing one solution with another, in a static approach. How can it give right directions to decision makers in order to support the vision of a circular economy? The application of different standards showed that it is not easy at all and that recycling product at their end of life are not rewarded equally and sometimes not promoted at all. Therefore rebound effects leading to contradictory decisions may occur. LCA alone is not enough to make enlightened decisions. It should be complemented by other methods. This was proposed in the last part. Based on the IPAT equation, this approach tries to capture different aspects that are not addressed properly by LCA, due to the fact that the functional unit is too restrictive, that the time dimension and prospective approach should be more integrated, and that it should enlarge the scale of the analysis to the macro-economy and the socio-economy. It should also recognize that the efforts have to be shared by different players including material industry and manufacturers, policy makers and society in general. As a general conclusion, we are convinced that tomorrow’s society will recognize the value of materials that are recyclable and reusable, like steel has been for many decades. But there is still a clear need to addressing, in research and development, the improvement of the metrics, combining social, environmental and economic assessment, so that the sustainability value of materials is properly measured. These are the objectives of the Sovamat Initiative and the SAM conferences.